Ebullition initiator



Patented Aug. 8, 1933 UNITED STATES PATENT osrlcl-z' 1,921,; EBULLITION mm'roa Application may 2. 1m. Serial Nt. 1ss,s5s 15 Claims. (cl. 62-126) Our invention relates to mechanical refrigerating systems and it bears particular reference tg means for preventing the superheating of the refrigerant employed therein.

Heretofore, it has been customary, in laboratories and the like to introduce into liquid being heated, and at a point adjacent to the point of highest temperature thereof, a quantity of loose small objects having relatively sharp'points which serve the purpose of causing ebullition to occur immediately upon the liquid reaching the .boiling temperature thereof. Ebullition initiators of this character are not adapted for service within a system requiring the circulation or movement of a liquid, or in a system in which the liquid is required to pass through ports of restricted area, owing to the fact that these small objects are apt to become displaced by the move-- ment of the liquid, thus preventing them from serving their purpose and at times interfering with the operation of .the system by closing or partially closing the relatively small. ports through which the liquid passes.

One object of our present invention is to apply the principal of initiating ebullition by mechanical means to mechanical refrigerating systems in order that ebullitio'n of the refrigerant may be caused to commence immediately upon the pressure of the refrigerant reaching the degree at which boiling should occur, which is, of course, dependent upon the existing temperature thereof.

Another object of our invention is to provide means for initiatingebullition which is simple and inexpensive to construct, durable in operation, which cannot become dislodged from its proper point of application and which exercises no deleterious effects upon either the refrigerant or the refrigerating system.

For a more detailed understanding invention reference may now be had to the accompanying drawing of which:

.Fig. 1 is a perspective view of an evaporator of a refrigerating system provided with an ebullition initiator embodying our invention.

Fig. 2 is a side elevational view of an ebullition initiator constructed in accordance with our invention. I I

Fig. 3 is a front elevation view of the device illustrated in Fig. 2.

Fig. 4 is a cross-sectional view of the device illustrated in Figs. 2 and 3, the section being taken substantially along the line IV-IV of P18. 2.

Figure 5 is a front elevational view of a conof our densing unit of a refrigerating system embodying the invention.

As illustrated in Figure 1, an evaporator 10 consisting of a horizontally disposed header member 11 which is adapted to contain refrigerant so in both liquid and gaseous form and is provided with depending hollow loops 12/ which are connected to the lower-most portion of theheader member 11, and are in open communication therewith. The headermember 11 has anend mems5 ber 13 secured thereto which is provided with suitable inlet port 14, to which is operatively connected a float valve 15 of the usualtype to control the rate of entry of the refrigerant into the header member 11 to maintain a predetermined level of liquid refrigerant therein. The end member 13 is also provided with an outlet port 16 of the usual type. 1

Disposed within at least one of the depending loops 12 is an ebullition initiator 20 which is composed of a relativelyv pliable metal; which is un-' I affected chemically by the refrigerant. When sulphurdioxide is employed as a refrigerant, the member 20 is preferably composed of copper. The member 20 consists of a relatively long wire having, a central portion 21 of relatively great thickness and having edged portions 22 which are flat and knurled to provide a plurality of relatively sharp projections. The lower end of the member 20 is bent into substantially U-shape ahd the extreme end 24 thereof is bent outwardly. The upper end 25 of. the member 20 is bent into the form of a loop, this loop serving as a handle and being of such diameter as will permit it to be inserted into the upper end of the depending tube 12, thus permitting of inserting the entire member 20 within the tube 12, and eliminating the possibility of the looped end projecting into the header 11 and interfering with the operation ofthe float 15. As the member 20 is inserted within the loop 12 it moves downwardly until the end portion engages the rounded bottom end of the loop 12, and, being pliable, it moves about the curved portiohthereof and moves upwardly a short distance into the opposite end of the loop, thus providing a plurality of sharp points at the bottom of the loop and in both legs of the loop. The outwardly bent portion 24 of the member 20 frictionally engages the slight irregularities in the inner surface of the loopmember 12, thus preventing displacement of the member 20 caused by movement of: the refrigerant therein or by vibration of the system caused by violent boiling of the liquid.

7 The refrigerant evaporator 10 is merely an element of a refrigerating system of a conventional design which is adapted to be operated in conjunction with any suitable refrigerant condensing unit 31 as illustrated by Figure 5. This unit embraces an electric motor 32 which drives a refrigerant compressor 34 by means of a belt 33. A refrigerant condenser 36, communicating with the high pressure side of the compressor 34, discharges condensed refrigerant liquid into a refrigerant receiver 3'1 from whence it is conveyed by a conduit 38 to the refrigerant evaporator 10. A conduit 39 communicating at one end with the low side of the compressor 34 is connectedat its opposite end to the evaporator 10 for the purpose of exhausting vaporized refrigerant fluid therefrom.

Our ebullition initiator, in its preferred contour, is formed by passing a substantially round soft copper wire between two opposed knurling rollers, each provided -with' a centrally disposed annular groove. These rollers force the wire into the form shown in Figure 4. The deformation and simultaneous knurling of the side flanges serve to render these portions somewhat hard and brittle, but the central portion, being altered but little in form and substantially uncompressed remains soft and pliable, thus preventing breakage of the member when subjected to bending. Thus the presence of the central portion of the member eliminates the necessity of annealing the ebullition initiator subsequent to the knurling operation. Also, the fact that sharp points are provided on the outer edges of the flanges 22 minimizes the possibility of the points being rendered ineffective by having oily sediment or the like deposited thereon.

Our invention contemplates employing ebullition initiators in as many loops as may be desired. In practice it has been found that a single device of this character will suffice, as the slight vibration caused by ebullition in the loop in which the initiator is disposed is sufficient to initiate ebullition in the remaining depending loops.

Although, we have illustrated but one form-of our invention and have described in detail but a single application thereof, it will be apparent to those skilled in the art that it is not so limited but that various changes and modifications may be made thereon without departing from the spirit of our invention or from the scope of the appended claims.

What we claim is: a

1. An ebullition initiator for a refrigerant expansion device comprising a metallic wire having knurled flanges. v

2. An ebullition initiator for a refrigerant expansion device comprising a copper wire having a smooth central portion and laterally projecting knurled flanges thereon.

3. An ebullition initiator for a refrigerant expansion device. comprising a metallic .member provided with a knurled portion, the end of said member being disposed at an angle to the main body portion thereof.

4. In combination a refrigerant vaporizer receptacle adapted to contain liquid refrigerant, means for initiating ebullition of the liquid in said receptacle, said means being adapted to clampingly engage the walls of said receptacle to prevent relative movement therebetween.

5. In combination a refrigerant vaporizer receptacle adapted to contain liquid refrigerant, means for initiating ebullitionof the liquid in said receptacle comprising a metallic ,member adapted to be inserted in said receptacle and provided with a relatively rough surface and bent to engage the walls of said receptacle.

6. In combination a refrigerant vaporizer receptacle adapted to contain liquid refrigerant, means for initiating ebullition of the liquid in, said receptacle comprising a knurled metallic, wire adapted to be inserted in said receptacle and adapted to frictionally engage'opposite walls. of said receptacle.

7. In combination a relatively long refrigerant vaporizer receptacle of restricted cross-sectional area and adapted to contain liquid refrigerant, means for initiating ebullition of said liquid comprising a metallic wire provided with a knurled portion and adapted to be inserted into said receptacle, a portion ofsaid wire being doubled back upon itself and disposed in engagement with one wall of the receptacle.

8. In amechanicaP refrigerating system an evaporator comprising a header provided with a plurality of depending portions in open communication therewith and adapted to contain refrigerant, means for initiating ebullition in said evaporator comprising'a member provided with relatively sharp points disposed in one of said depending portions, said member being composed of a metal which is unaffected chemically by the refrigerant. I

9. A refrigerating system comprising a refrigerant evaporator having a quantity of refrigerant liquid therein, a member projecting within the liquid for initiating ebullition thereof beneath the surface, and means'for maintainingthe last mentioned means in a definite position within the evaporator.

10. A refrigerating system comprising an evaporator including a tube,'said evaporator and tube an ebullating member projecting within the tube for initiating evaporation therein whereby the temperature of the liquid in the evaporator is maintained at a substantially constant value.

11. A refrigerating system comprising an evaporator having a quantity of refrigerant liquid therein, said evaporator including a curved tube filled with said refrigerant, and a flexible member extending within the tube for initiating vaporization of the liquid therein.

, containing a quantity of refrigerant liquid, and

12. A refrigerating system comprising an evap orator for containing a quantity of refrigerant liquid and a relatively long flexible member for insertion into the evaporator beneath the level of the liquid therein, said member having means associated with the surface thereof for initiating evaporation of the liquid.

13. An ebullition initiator for a refrigerant expansion device comprising a metallic wire knurled throughout a substantial portion of its length.

14. A refrigerating system comprising an evaporator having a quantity of refrigerant therein and ebullition means submerged in said liquid adjacent the lowermost part of the evaporator, said means having surfaces which contact with said refrigerant liquid and which have a lower interfacial tension with vapor than with the refrigerant within which it is submerged so as to allow free passage of liberated vaporto the vapor space in the evaporator. w 7 15. A refrigerating system comprising an evaporator liaving duct means containing a quantity '15( a lower interfacial tension with said liquid that between the liquid and the liquid engaging surfaces of the evaporator, whereby to initiate the formation of refrigerant vapor beneath the surface of the liquid.

with said liquid refrigerant, said surfaces having CARLE'I'ON J. 'LAUER. mom a. McPHAIL. 

